1. Field of the Invention
The present invention relates to a charging member used in electrophotographic apparatuses and a method for manufacturing the same.
2. Description of the Related Art
In an electrophotographic apparatus, electrographic members are used, and examples of the electrophotographic member includes a charging member for charging an outer surface of a photosensitive member by being into contact with the outer surface, a developing member for developing an electrostatic latent image formed on the outer surface of the photosensitive member to form a toner image and a cleaning member for removing toner attached to the photosensitive member.
As the charging member used herein, a charging member having a supporting member and an elastic layer (conductive elastic layer) provided on the supporting member is generally employed in view of keeping a sufficient abutting nip with the photosensitive member. Furthermore, to suppress adhesion of a developer, etc., to the surface of the elastic layer, a surface layer is generally provided to the surface of the elastic layer.
Japanese Patent Application Laid-Open No. 2007-004102 discloses a charging member having a surface layer, which is formed of polysiloxane having a fluoroalkyl group and an oxyalkylene group by a so-called sol-gel method. By the presence of a site of a fluoroalkyl group, surface free energy is lowered. By virtue of this, a toner and external additives used in the toner are rarely adhered to the surface even if the member is repeatedly used for a long time. As a result, it is described that the charging member, if it is employed in a DC contact charging system, can be used as a charging member capable of stably charging and outputting images for a long time.
Furthermore, as a method for suppressing adhesion of dirt to the surface of an electrographic member, a method of appropriately roughening the surface of the surface layer by adding coarse particles to the surface layer is known, as described in Japanese Patent Application Laid-Open No. 2009-009028.